Organometallic ruthenium(II) complexes: Synthesis, structure and influence of substitution at azomethine carbon towards DNA/BSA binding, radical scavenging and cytotoxicity

Bivalent, ruthenium organometallics containing hydrazone ligands with the composition [RuH(CO)(PPh3)2(L1−3)] (4–6) have been synthesised from the reactions of [RuH2(CO)(PPh3)3] and benzoic acid pyridine-2-ylmethylene-hydrazide (HL1) (1) /benzoic acid (1-pyridin-2-yl-ethylidene)-hydrazide (HL2) (2)/benzoic acid (phenyl-pyridin-2-yl-methylene)-hydrazide (HL3) (3) and characterised by various physico–chemical techniques. The X-ray crystal structure of one of the above complexes, [RuH(CO)(PPh3)2(L3)] (6) demonstrated a distorted octahedral coordination geometry around the metal centre. Results of our investigation on the effect of substitution (H or CH3 or C6H5) at the azomethine carbon of coordinated hydrazone in these ruthenium chelates on the potential binding with DNA/BSA, free radical scavenging and cytotoxicity is presented. Ruthenium(II) organometallic hydrazone complexes were synthesised, characterised and biological evaluations were carried out. [Display omitted] ► Synthesis of new ruthenium carbonyl hydrazone complexes with octahedral geometry. ► All the new complexes showed significant interaction with both DNA and protein. ► Free radical scavenging and cytotoxicity results proved their efficacy.